A 49-year-old Castro Valley man was shot and wounded by an Alameda County sheriff's sergeant after allegedly pointing a fake gun at deputies, authorities said.

The man, whose name was not released, underwent surgery at Eden Medical Center after he was shot about 7 p.m. Friday. He remained in critical condition Saturday.

The incident began when deputies were called to the home on Seven Hills Road by family members to investigate reports that the man was making threats and being abusive, authorities said. The man himself then called the sheriff's office and said he would shoot any deputies who came to the home, investigators said.

An armored sheriff's vehicle came to the scene and deputies saw the man ducking behind juniper bushes while armed with what appeared to be a rifle, authorities said.

A sergeant stationed at a porthole on the armored vehicle opened fire when the suspect again pointed the object at deputies, authorities said. Deputies said they later determined that he had been holding a fake gun made of wood, with a handle made to resemble a rifle.